This invention relates to an open architecture superconducting magnet assembly for a magnetic resonance imager (hereinafter called "MRI"), and more particularly to an adjustable, versatile assembly which facilitates interventional procedures.
Most MRI equipments utilize solenoidal magnets enclosed in cylindrical structures with a central bore opening for patient access. However, in such an arrangement, the patient is practically enclosed in the warm bore, which can induce claustrophobia in some patients. The desirability of an open architecture in which the patient is not essentially totally enclosed has long been recognized. Unfortunately, an open architecture structure poses a number of technical problems and challenges. Such an arrangement must still be capable of generating the very uniform yet strong magnetic fields required.
Another important application of open MRI magnet assemblies is for interventional procedures wherein the physician or surgeon can access the patient for such procedures while observing the display of a selected internal portion of the patient such as the region being operated on or treated for example, by lasers or by surgical instruments or mechanisms inserted into the patients blood vessels or organs.
Such procedures require open space for the surgeon to operate and simultaneous optimum MRI display viewing of the selected region of the patient receiving the operation. These at times conflicting objectives may require an adjustable magnet assembly in which the positioning of the magnets forming the imaging area magnet field is adjustable about a patient supported in various positions and inclinations. The magnet assembly at the same time needs to provide a sufficiently strong and homogenous field in the imaging region, and adjustment of the magnetic field orientation.
In addition, it is highly desirable that such selective adjustments enable the positioning of the magnet assembly on animals in veterinary applications and patients who may be in a wheel chair, on a table and/or in various inclinations to facilitate maximum surgeon intervention space while at the same time providing enhanced surgeon viewing.